---
title: "Bored cast-in-situ pile procedure"
subject: "Foundation Engineering"
chapter: 8
key: "semester_5/foundation_engineering:bored-cast-in-situ-pile"
source: https://www.bctengineer.com/q/semester_5/foundation_engineering/bored-cast-in-situ-pile
site: BCT Engineering
---

# Bored cast-in-situ pile procedure

Foundation Engineering · Chapter 8: Pile Foundations

- Asked in: 2082 Bhadra, 2 marks
- Video: [Bored Piling Explained | 𝐆𝐞𝐨𝐭𝐞𝐜𝐡𝐧𝐢𝐜𝐚𝐥 𝐅𝐨𝐮𝐧𝐝𝐚𝐭𝐢𝐨𝐧](https://www.youtube.com/watch?v=3yYYCqz5sb4) — Geohan Media
- Answer checked by Claude Sonnet 5.5 on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/foundation_engineering/bored-cast-in-situ-pile
- Whole chapter: https://www.bctengineer.com/md/semester_5/foundation_engineering/chapter-8

## Question

Explain the procedure for constructing bored and cast-in-situ pile.

## Short answer

Construction involves drilling a hole under slurry or casing, cleaning, placing reinforcement, and placing concrete via a tremie pipe from bottom up, displacing slurry. The casing is gradually withdrawn as concrete rises, then the pile head is cured and cut to the cut‑off level.

## Answer

A **bored cast-in-situ pile** is formed by drilling a hole in the ground and filling it with reinforced concrete. Because soil is removed, there is little displacement and vibration.

#### Procedure
1. **Set out** the pile position and set up the boring rig (auger or rotary).
2. **Boring:** drill the hole to the required depth. In loose or collapsing soil use a temporary casing or **bentonite slurry** to keep the hole stable.
3. **Cleaning:** remove loose soil and cuttings from the bottom (using a cleaning bucket) and check depth and verticality.
4. **Reinforcement:** lower the prefabricated steel cage with spacers.
5. **Concreting:** place concrete through a **tremie pipe** from the bottom up (so that it does not segregate), keeping the tremie embedded in the concrete. The slurry is displaced upwards.
6. **Casing withdrawal:** pull out the casing as the concrete rises, keeping enough concrete head inside.
7. **Curing and cut-off:** after setting, cut the pile head to the cut-off level and connect to the pile cap.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. In collapsing soil the hole is stabilised by:
   A. Temporary casing or bentonite slurry
   B. Dry sand
   C. Ramming
   D. Pumping air
   Answer: A. Casing or slurry supports the sides. (Key point: Stability of hole)

2. Why is a tremie pipe used?
   A. To place concrete from the bottom up without segregation
   B. To drill
   C. To clean the hole
   D. To cut the pile head
   Answer: A. The tremie stays embedded and displaces slurry upwards. (Key point: Tremie)

3. What comes before concreting?
   A. Lowering the reinforcement cage after cleaning
   B. Cut-off
   C. Curing
   D. Casing withdrawal
   Answer: A. Boring, cleaning, then cage, then concrete. (Key point: Order)

4. Bored piles cause:
   A. Little displacement and vibration
   B. Large heave
   C. High noise
   D. Compaction
   Answer: A. Soil is removed rather than displaced. (Key point: Soil effect)

## Related in Foundation Engineering

- [Anchored sheet pile, free earth procedure](https://www.bctengineer.com/question.md?key=semester_5%2Ffoundation_engineering%3Aanchored-sheet-pile-free-earth-procedure) — Foundation Engineering, chapter 5

## Related in other subjects

- [Sheet pile flow net; graded filter](https://www.bctengineer.com/question.md?key=semester_4%2Fsoil_mechanics%3Asheet-pile-flow-net-graded-filter) — Soil Mechanics, chapter 7